Skip the auto shop - Our mechanics make house calls

Q: Engine puffs blue smoke; thumping noise at highway speeds

asked by on

In the mornings when I start my SUV, for a few seconds the engine puffs blue smoke. When I’m driving on the highway at 60 mph, it begins to make a very obnoxious thumping sound that can also be felt by the vibrations. It feels like there is something stuck to the tire, but when I examine them, I don’t find anything. With more speed, the louder it becomes. I have looked at the transmission, driveline, shafts - all seem fine. Another problem is that when I am braking, the steering wheel shakes and there is a loud noise under the brake pedal. I have already changed the brake pads and the rotors, machined them, etc. No repairs have worked! I would greatly appreciate your advice on what will fix my car. Thanks.

Hi there, thanks for asking about your 2004 Infiniti FX45. The blue smoke you notice on initial start-up is likely caused by worn exhaust valve stem seals. They allow a tiny amount of oil to get into the combustion chamber while the car sits overnight. This will slowly get worse with additional miles until the valve stem seals are replaced. Have the front tires and wheels checked for balance, "roundness", or any separation of the tread of the tire at a reputable tire dealer. There is likely something amiss that’s showing up at highway speed and under braking. If you want to have this checked by a certified mechanic, a technician from YourMechanic can come to your home or office to inspect the smoke coming from your car’s exhaust.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Does my car need new brake pads and rotors?

Hi there: In most instances, if the brake pads have not fully worn out, the rotors will not suffer scarring or pitting which typically means the rotors need to be surfaced or replaced. However, it really depends on the damage...

Q: White smoke from exhaust

Hello. White smoke out of the exhaust usually means that there is coolant getting into the cylinder head, or engine block. The most common cause of this is a blown head gasket. This means that the head gasket that sits...

Q: Should I be able to spin front wheel by hand while other wheel is on the ground

Hey there, thanks for writing in about your 2002 Jeep Grand Cherokee. Make sure that you are not in four-wheel drive mode. Sometimes when the hubs lock, they make a clunking noise and the whining noise could be a gear...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...